From b6b9915ad0b9c70c3b7edc45dfca2fdcfd4ba5cb Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Thu, 11 Aug 2022 13:59:34 +0100
Subject: [PATCH] drm/vc4: Set AXI panic modes for the HVS

The HVS can change AXI request mode based on how full the COB
FIFOs are.
Until now the vc4 driver has been relying on the firmware to
have set these to sensible values.

With HVS channel 2 now being used for live video, change the
panic mode for all channels to be explicitly set by the driver,
and the same for all channels.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/gpu/drm/vc4/vc4_hvs.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -1149,6 +1149,17 @@ static int vc4_hvs_bind(struct device *d
 	dispctrl |= VC4_SET_FIELD(2, SCALER_DISPCTRL_PANIC1);
 	dispctrl |= VC4_SET_FIELD(2, SCALER_DISPCTRL_PANIC2);
 
+	/* Set AXI panic mode.
+	 * VC4 panics when < 2 lines in FIFO.
+	 * VC5 panics when less than 1 line in the FIFO.
+	 */
+	dispctrl &= ~(SCALER_DISPCTRL_PANIC0_MASK |
+		      SCALER_DISPCTRL_PANIC1_MASK |
+		      SCALER_DISPCTRL_PANIC2_MASK);
+	dispctrl |= VC4_SET_FIELD(2, SCALER_DISPCTRL_PANIC0);
+	dispctrl |= VC4_SET_FIELD(2, SCALER_DISPCTRL_PANIC1);
+	dispctrl |= VC4_SET_FIELD(2, SCALER_DISPCTRL_PANIC2);
+
 	HVS_WRITE(SCALER_DISPCTRL, dispctrl);
 
 	/* Recompute Composite Output Buffer (COB) allocations for the displays
